A teenager helped rescue her two sisters from a serious house fire today, a fire service said.

The 13-year-old youngster raised the alarm and stayed on the phone with a fire control operator as she and her sisters escaped from the burning home in Penrhyn Bay, near Llandudno, north Wales.

A 32-year-old woman, thought to be their mother, and a 38-year-old man are both in a critical condition in hospital and another 32-year-old woman is in a serious but stable condition, North Wales Fire Service said.

The alarm was raised by the girl, who has not been named, shortly after 12.30am and firefighters arrived to find the property heavily smoke-logged.

Five fire crews used six sets of breathing apparatus, four hose reel jets and one main jet to tackle the blaze and rescue the three adults from the first floor.

An investigation is under way to establish the cause of the fire.

North Wales Fire and Rescue Service praised the girl who rang for help.

Senior operations manager Gary Brandrick said: “Her actions helped to ensure she and her two sisters escaped safely from the house.

“She notified us of the fire and of the fact that there were a further three adults in the upstairs of the building.

“The children were alerted to the fire by a smoke alarm.

“We carried out a home fire safety check at the address in September last year, in 2010, when we fitted two smoke alarms and advised the family of fire safety precautions they should take – such as testing the smoke alarms regularly, the importance of having a night-time routine and of formulating a family escape plan.

“The early warning signal provided by the smoke alarms clearly helped the children to call for help and to make their way out of the property.

“We would appeal to all residents in North Wales to take advantage of our free home fire safety checks.”